PEROXYACETYL NITRATE - REVIEW OF TOXICITY

PAN is one of a class of common air pollutants formed by the action of sunlight on volatile organic compounds and nitrogen oxides. No toxico kinetic studies have been found in the available literature. The acute toxicity of PAN is less than that of ozone, similar to NO2 and higher than SO2. The LC50 in mice and rats were 718-743 mg/m(3) (for 2 h) an d 470 mg/m(3) (for 4 h), respectively. Following acute exposure, sever e lung lesions and, at the higher levels, damage to the epithelium of upper parts of the respiratory tract were found in animals. It seems t hat concentrations of 1.19-1.49 mg/m(3) lie not far from the threshold required for pulmonary function effects in sensitive individuals. How ever, these PAN concentrations are well above the maximum ambient conc entrations usually experienced within the USA and Canada (0.003-0.078 mg/m(3)). It appears unlikely that present ambient PAN concentrations would affect pulmonary lowest level causing eye irritations was 0.64 m g/m(3) for 2 h. Concentrations of 0.99 and 4.95 mg/m(3) were identifie d as no-observed-effect level (NOEL) and no-observed-adverse-effect le vel (NOAEL) for pathological and histological changes in the respirato ry system (nasal passages) of rats during subchronic exposures to PAN, but were not considered to be relevant to derivation of a RfC for chr onic inhalation exposure. PAN is a weak point mutagen or clastogen. Th e data are not sufficient to evaluate its carcinogenicity. No study wa s found which could be used for the derivation of a RfC for acute or c hronic inhalation exposure to PAN.